1. Field of the Invention
The present invention relates to muffler units and vehicles including the muffler units.
2. Description of the Related Art
Vehicles that include engines are conventionally provided with mufflers to reduce exhaust noise associated with discharge of exhaust gas from the engines. The engine and muffler of such a vehicle are connected to each other through an exhaust pipe. For example, when the muffler has a cylindrical shape, the exhaust pipe may be connected to the muffler in an axial direction of the muffler or in a radial direction of the muffler so that the muffler supports the exhaust pipe.
Examples of such a vehicle include vehicles designed to be travel over rough terrain. Among these vehicles are a recreational off-highway vehicle (hereinafter referred to as an “ROV”) and a side-by-side all terrain vehicle (ATV). Because such a vehicle is subject to strict constraints of the installation space for the muffler and the exhaust pipe, the exhaust pipe is often connected to the muffler in the radial direction of the muffler. When such a vehicle travels over rough terrain, the engine, exhaust pipe, and muffler of the vehicle vibrate more strongly than when the vehicle travels over flat terrain. For example, U.S. Pat. No. 8,596,405 discloses a vehicle including an engine; a first exhaust pipe connected to the engine; a second exhaust pipe connected to the first exhaust pipe; and a muffler connected to the second exhaust pipe. The second exhaust pipe and the muffler define a muffler unit. In the muffler unit, the second exhaust pipe is connected to the muffler in a radial direction of the muffler.
In the vehicle disclosed in U.S. Pat. No. 8,596,405, the second exhaust pipe is connected to the muffler in the radial direction of the muffler at a single position. In other words, the muffler supports the second exhaust pipe at the single position. The vehicle traveling over rough terrain causes the second exhaust pipe and the muffler to vibrate, or causes one of the second exhaust pipe and the muffler to vibrate when the other of the second exhaust pipe and the muffler is secured. In this case, stress caused by such vibrations concentrates at the connection between the second exhaust pipe and the muffler. This unfortunately creates the need for a robust structure to reduce distortion that occurs in the connection due to the stress.